Binding of phytochrome B to its nuclear signalling partner PIF3 is reversibly induced by light
Binding of phytochrome B to its nuclear signalling partner PIF3 is reversibly induced by light
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DOI：
10.1038/23500
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发表时间：
1999-08-19
期刊：
影响因子：
64.8
通讯作者：
Quail, PH
中科院分区：
文献类型：
--
作者：
Ni, M;Tepperman, JM;Quail, PH
光敏色素光感受器家族响应红色和远红光子的连续吸收，通过在生物非活性和活性构象异构体之间切换来指导植物基因表达(1,2)。已鉴定出几种在光敏色素信号转导通路晚期发挥作用的中间体，但在该通路早期发挥作用的中间体较少(3,4)。我们克隆了一种核碱性螺旋-环-螺旋蛋白 PIF3，它可以与光敏色素 A 和 B 的非光活性羧基末端片段结合，并在体内光敏色素信号传导中发挥作用 (5)。在这里，我们表明，全长光活性光敏色素 B 仅在光诱导转化为其活性形式时才在体外结合 PIF3，并且光转化回其非活性形式会导致与 PIF3 解离。我们得出结论，光敏色素 B 的光传感信号涉及光诱导的、对假定的转录调节因子 PIF3 的构象异构体特异性识别，为基因表达的直接光调节提供了潜在的机制。
The phytochrome photoreceptor family directs plant gene expression by switching between biologically inactive and active conformers in response to the sequential absorption of red and far-red photons(1,2). Several intermediates that act late in the phytochrome signalling pathway have been identified, but fewer have been identified that act early in the pathway(3,4). We have cloned a nuclear basic helix-loop-helix protein, PIF3, which can bind to non-photoactive carboxy-terminal fragments of phytochromes A and B and functions in phytochrome signalling in vivo(5). Here we show that full-length photoactive phytochrome B binds PIF3 in vitro only upon light-induced conversion to its active form, and that photoconversion back to its inactive form causes dissociation from PIF3. We conclude that photosensory signalling by phytochrome B involves light-induced, conformer-specific recognition of the putative transcriptional regulator PIF3, providing a potential mechanism for direct photoregulation of gene expression.